Magnetic core and coil assembly



J J O'CALLAGHAN IAGIETIG CORE AND COIL `ASSEMBLY Filld Supt. 10, 1935 ILT/Are? Gu; Mya/A16 /7 fig-3 July Z 1940.

A TTORNEYS.

Patented July 2, 19.40 l I rUNITED STATES PATENT OFFICE MAGNETIC CORE AND COIL ASSEMBLY Jerome J. OCallaghan, Chicago, Ill., assignor to Ferrocart Corporation of America, New York, N. Y., a corporation of Delaware Applieenn september 1o, 1935, serial No. 39,889

s claims. (o1. 1754-359) This invention relates to means and methods core member and the spacer members are accuof assembling magnetic cores and electrical coils rately made to exactly fit Within the sleeve I, and in simple, accurate, predetermined and constant the sum of their lengths is alittle less than the mechanical relationships, so that equally acculength'of the sleeve so that they may all be 5 rate and constant desirable electrical characpressed iirmly together and in permanently asteristics may be simply and economically obsembled relation by deforming the ends 5 and 6 tained. In examples presented here the adaptaf the sleeve I to provide positioningA and retions are essentially for use in radio receivers but taining shoulders. The end of the paper tube the invention is not restricted thereto, is desirably deformed before the core and spacer It is an object of this invention to provide a members are inserted, and the end'S is deformed 10 simple means of associating a magnetic core and after they have been inserted.v Other means electrical coil in a desirably predetermined relathan the spacers 3 and 4 and deformed tube ends tionship. 5 and 8 may be employed, if desired, for holding It is a further object of the invention to prothe parts together. e

vide a coupling device which can be made accu- TheaSSemblY thus DrOVidefiS placed in a wind- 15 rately and inexpensively, and which is mechaning' jig- The cOre member Vi. due to the accuically sturdy and dependable in use. rately determined length of spacer 4, is located It is a further object of the invention to pro- 'longitudinally of the sleeve with reference to the vide a novel method of constructing the coupling shoulder formed by the end portion 5, and hence device whereby the desired characteristics may a Winding machine Setting iS used Which will 20 be accurately secured with a minimum of labor. cause coil 'I to be wound about the middle portion and skill, and whereby a highly eiilcient durable 0f the core member 2- The ends 0f the C0i1 Windstructure may be economically produced. e ing are preferably 0f Such length that they may It is a`stillv further object to provide a simple be connected directly to the respective terminals means of mounting `the magnetic core and elec- Y 8 and 9. The assembly may then be dipped in 25 trical coil assembly to other structural units in an insulating wax which forms a coating over desirable relationships. the coil and the adjacent portions of the sleeve Other objects and advantages will hereinafter l tObOnd the parts tOgether and exclude moisappean ture. The electrical terminals 8 and 9 may be In the drawing forming part of this specifcavriveted or eyeleted into an insulating terminal 30 tion; 1 strip I0 which is in turn fastened to the assem- Figure 1 is a view in elevation of one of the bly of core and coil by the screw II. Wood screws assembly units turned on its side, the shield or may be used With WOOdeIl Spacer blocks 3 but housing being omitted; machine screws arepreferable when the spacer` Figure 2 is a cross section of the structure illusblocks are formed of other and harder insulat- 35 trated in Figure 1. ing material.

Figure is a view in elevation of a coupling A threaded Stem l2 may be Screwed intO an structure involving more than one core and coil. axial bore 0f the Spacer block 4 andA extend Out- Figure 4 is a sectional detailed view illustrate Ward beyond the end of the sleeve in axial align- 'l 40 ing the sleeve and coil assembly of Figure 3. ment with the sleeve I and with the parts mount- 40 In making the assembly illustrated in Figure ed in and upon the sleeve. The stem I2 may be l 1 and Figure 2, provision is iirst made of a sleeve used for mounting the complete assembly lin a I oi insulating material such as a paper tube. shield can, orI to a base plate, or to any asso- The cylindrical sleeve may be polygonal in crossciated apparatussection but is preferably of' eircuiar eross-sec- In Figure 31s shown an assembly involving the 45 tion and in any case its' transverse dimensions same type 01' Sleeve l but with two coils I3 and are accurately controlled and it has suilicient I4 mounted in spaced relaticnship. while the rigidity to constitute per se the support for' the cross section of Figure 4 indicates the assembly magnetic cores and associated coils. A magof the various parts comprising Figure 3. As benetic core member 2 is inserted in the sleeve before, one end of the sleeve I is turned over at the 5o tween 'the insulating spacer members 3 and l, end 5 and a spacer block I5 is inserted from the desirably of wood. 'I'he magnetic core member open end. Amagnetic core I6, followed by spacer may be of laminated -construction but is pref- I1, magnetic core I8, and spacer I9 are then erably composed of powdered iron which is united inserted; The end 6 is then deformed to hold the ,u by a suitable insulating binder and molded. The components in xed relationship. If not needed l5 for mounting purposes, the spacer clock I5 and/or the spacer block I9 may be omitted.

Two small adjustable condensers of the compression type are shown mounted upon the insulating block 20, one on either side of the threaded stem I2 which connects the insulating block to the core and coil assembly. The coils may be `connected to terminals of the condensers assembled on the insulating block 20. The capacity may be varied so as to adjust the electrical characteristics.

Conductors 2| and 2| are connected respectively to the terminals of the condensers mounted on the insulating block 2|) and constitute Wires leading to other electrical circuits. An insulating spacer sheet 22, desirably formed of paper, is secured to the spacer block I5 by a screw 23 and serves to hold the conductors 2|, 2| in predetermined positions, thus avoiding changes in the magnitudes of the inherent capacitive couplings between the conductors and the coils. Near each of its four corners the sheet 22 has an opening for 4receiving one of the conductors 2|, 2|. The spacer plate 22 causes the conductors 2|, 2| to extend past the coils in substantially parallel relation to the common axis of the coil and at a uniform distance therefrom. While in the figures thus far shown the coils are mounted centrally with respect to the magnetic cores, this is not a necessary limitation and any desired relation may be used. The essential feature is the use of accurate length cores and spacers inside the sleeve so that any measurable assembly external to the sleeve will have proper relationships to the cores and spacers inside.

The entire assembly thus far described may be inserted into -a metallic shielding housing.

The structure shown and described is capable of being made with great accuracy and yet in an economical manner. All the .parts are definitely and accurately fixed in predetermined relation and the mechanical arrangement. is such that the parts do not get out of place in the course of shipping or ordinary use. A high degree of electrical uniformity may be secured, and this will be maintained indefinitely in the use oi' the structure.

I have described what I believe to be the best embodiments of my invention. I do not wish, however, to be confined to the embodiments shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

I claim:

1. In a coupling device for electrical circuits, in combination, an insulating sleeve comprising a relatively rigid paper tube of circular cross-section, a pair of cylindrical core blocks inserted in nthe sleeve, a spacer block of non-magnetic material in the sleeve and interposed between the core blocks for holding them separated a predetermined distance, coils wound upon the sleeve about the respective core blocks, and means including a second spacer block for mounting the sleeve upon a support, said second spacer block spacing the adjacent core block from one end of the sleeve.

2. The method of making transformers which comprises providing an insulating sleeve having one end formed to provide an internal shoulder, inserting permeable core blocks and insulating spacer blocks in alternation through the opposite end of the sleeve, deforming the last mentioned end of the sleeve to fix the ,inserted blocks in place,` and winding coilsupon the sleeve in desired relations to the respective core blocks.

3. In an inductive device for use at radio frequencies, a substantially rigid tubular sleeve of paper, axially alined magnetic core and spacer blocks tightly fitted into said sleeve in alternations, said blocks being located entirely within and extending approximately lfrom end to end of said sleeve, means comprising the inturned ends of said sleeve for retaining said blocks in fixed positions within said sleeve, and a coil mechanically supported by and at the exterior of said sleeve, said coil being positioned about a magnetic core block.

4. In a coupling device for radio circuits, an insulating sleeve comprising a cylindrical paper tube of circular cross-section, magnetic core blocks and insulating spacer blocks axially arranged in alternation within and substantially completely filling said sleeve, said core blocks having exterior surfaces conforming to and snugly engaging the interior of said sleeve, the ends of said sleeve being deformed to retain said blocks in place, and a plurality of coils mechanically supported by and at the exterior of said sleeve, said coils being positioned about the respective magnetic core blocks.

5. In a transformer for radio frequency circuits, a tubular insulating sleeve of paper, a pair of magnetic core blocks and a plurality of non-magnetic spacer blocks tightly fitted within and substantially completely filling the interior of said sleeve, said magnetic core blocks and spacer blocks being arranged in alternation with a spacer block at each end of said sleeve, coils supported by said sleeve and surrounding the respective magnetic core blocks, and means including a stem secured to one of said spacer blocks at an end of said sleeve for mounting the assembly.

6. An inductance for use at radio frequencies, said inductance comprising a paper tube, a single core of magnetic material within and `having an exterior surface conforming to and snugly engaging the interior surface of the paper tube, a spacer block between said core and one end of said tube, said spacer block being of insulating material and frictionally held in place within said tube, and a coil wound in situ upon said tube after said core and spacer block are positioned within the papertube.

7. In an inductance for use at radio frequencies, an insulating sleeve, a magnetic core located within and frictionally engaging said sleeve, a nonmagnetic spacer member within said sleeve for positioning said core in predetermined axial displacement from one end of said sleeve, a coil supported on and at the exterior of said sleeve to surround said core, and means detachably secured to Asaid spacer member formechanically supporting said sleeve, core and coil.

8, In the manufacture of radio' frequency inductances, the process of forming core assemblies for receiving the windings which comprises providing an insulating sleeve having one end formed to provide an internal shoulder, inserting a plurality of alternately arranged magnetic core and non-magnetic spacer blocks into said sleeve through the other end thereof, and deforming said other end of the insulating sleeve to fix the inserted blocks in predetermined locations within said sleeve. Y

JEROME J. OCALLAGHAN. 

